Referring to FIGS. 1 and 2, a conventional walker 1 as disclosed in Chinese Patent No. 2796692Y includes a front frame 11 having two sleeve tubes 111, two side frames 12 each having a front leg 122 rotatably inserted in a respective one of the sleeve tubes 111, and two locking units 13. Each side frame 12 has a horizontal support arm 121 extending horizontally and rearwardly from the front leg 122 for mounting a hand grip thereon.
Each locking unit 13 has amounting seat 15 sleeved and secured on the front leg 122 by means of a fastener 101, an upright locking pin 16 movably disposed in a pin hole 152 of the mounting seat 15, a biasing spring 17 sleeved around the locking pin 16 to bias the locking pin 16 upwardly, and an actuating lever 18 pivotably connected to the front leg 122 at a middle portion 182, and having an actuating and manually operated portions 181, 183 at the front and rear sides of the middle portion 182, respectively. An upward pulling action on the manually operated portion 183 results in downward movement of the actuating portion 181, pressing the locking pin 16 out of a lock opening 143 of an arcuate slot 141 so as to permit movement of the locking pin 16 along the arcuate slot 141. Therefore, the respective side frame 12 can be turned relative to the front frame 11 in folded and unfolded positions.
However, the manually operated portion 183 is disposed under and proximate to the hand grip for facilitating operation, which takes up the gripping space for the user and interferes with the walking of the user using the foldable walker.
Referring to FIG. 3, another conventional foldable walker as disclosed in U.S. Pat. No. 6,886,575 has the locking unit 13 further having a connecting rod 19 which is connected between the actuating lever 18 and the locking pin 16. An upward pulling action on the actuating lever 18 causes the connecting rod 19 to be pulled in an upward direction so as to raise and withdraw the locking pin 16 from the lock opening 143. The presence of the actuating lever 18 that takes up the gripping space causes inconvenience during use of the foldable walker.